HTML5 webcam to canvas stream (Demo + annotated code)

http://cbrandolino.github.com/camvas

by cbrandolino_ • 14 years ago

60 24 14 years ago

cbrandolino.github.com

ionwake5• 14 years ago

the FPS are really low - is there a way to improve that?

I'm afraid it depends on the browser implementation. It works fine on Chrome 12 odd on linux, with all hardware accelerations activated under chrome://flags/

ionwake5• 14 years ago

i had around 2fps - is the res too high?

drivebyacct2• 14 years ago

Chrome 12? Where do you even get that? I'm on Chrome 23.

program• 14 years ago

I got nice quality on Chrome 21. Substitute the window.requestAnimationFrame directive with:

  window.requestAnimationFrame = (function() {
    return window.requestAnimationFrame || window.webkitRequestAnimationFrame ||
    window.mozRequestAnimationFrame || window.oRequestAnimationFrame ||
    window.msRequestAnimationFrame || function(callback) { window.setTimeout(callback, 1000 / 60); };
  })();

and it will work in Opera 12 too.

cbrandolino_7• 14 years ago

Wow, I was sure they implemented requestAnimationFrame already!

Anyway, I limited myself to trying out the various vendors' prefixes; this being mainly an experiment/preview I'd rather keep the code clean than support non-cutting-edge browsers.

I'll update the paragraph about the compatibility though; thanks for the heads up!

ionwake5• 14 years ago

what is p2p performance like? what amount of code would have to be written?

cbrandolino_7• 14 years ago

Well, for what concerns the part I focused on (the canvas part) there should not be any performance issue with p2p.

For WebRTC p2p video streaming in general, it seems promising. At the moment, though, there's little to no browser support and getting a full system (there's also a server involved, to initiate the connections) is not automated or abstracted yet.

For more info, check out this page: http://www.webrtc.org/running-the-demos

franze2• 14 years ago

hi, this is as good a moment as any to promote a little bit a lib i coded some time ago.

a simple (cross browser) wrapper to make getUserMedia really simple, you call

  Sinne.getUserVideo(success, error[, options])
  //https://github.com/franzenzenhofer/Sinne

and get back a nice HTML5 video element with the webcam as the input

here is a simple demo using the `Sinne` http://www.backpacker.io/ - an HTML5 mirror

se852• 14 years ago

You can't really call it cross browser when it doesn't support browsers that don't have getUserMedia.

You had me excited for a second there because something like this with a flash fallback mechanism would be really, really useful.

franze2• 14 years ago

addy osmani has coded https://github.com/addyosmani/getUserMedia.js which has a flash fallback, but the thing is that the flash fallback still needs you to implement a complete different logic then getUserMedia, so it's far from a perfect solution.

i raised the issue here https://github.com/addyosmani/getUserMedia.js/issues/2#issue... (and suggested a possible solution), but for this we would need the help of a flash megamind-ninja.

cbrandolino_7• 14 years ago

Nice lib!

I was thinking of libifying my thingy, in a quite minimalistic way (at a minumum, the user would just pass two functions, one "update" and one "draw", which would receive a the current frame and, in the first case, the delta time).

This way you could just get freaky with the canvas effects and composing capabilities and stop caring about the low-level stuff.

I see you know your way around building nice, clean APIs; could you suggest me article/book about it? I'm kind of a newbie to that sort of things.

bencevans• 14 years ago

I wrote a li'l app that does something along the same lines. However it captures a data uri from the webcam video and sends it via a websocket to a second user who's also doing the same. It gives you a video chat just without the audio... https://github.com/bencevans/MediaStream

Just thought it may be of interest ;)

jayniz• 14 years ago

SLOW CLAP

cbrandolino_7• 14 years ago

Oh you! Can you suggest a gif? ^^

cbrandolino_7• 14 years ago

Uh, from the downvotes I gather that was inappropriate. Sorry; I'm completely new to HN.

Anyway the backstory is that me and jayniz used to work together, and he usually adds a gif to each of his readme files.

Jelte12345• 14 years ago

Strange enough my performance is real crappy (3fps) when I launch it, but when I switch to another tab and back it's great. This happens on Chrome 21 with none of the flags enabled.

dkroy• 14 years ago

Really cool, keep up the good work. It works in Google Chrome 21.0.1180.89, on Windows 7 just fine.

jlsync• 14 years ago

Last weekend at #devfestlondon I attempted streaming and sharing these video streams over socket.io with a node.js backend. Demo is http://svideo.herokuapp.com/ and http://svideo.jit.su/ - your image stream is shared on the internet.

ukc• 14 years ago

Looking forward to seeing more projects like these - is the heroku app open source?

HTML5 webcam to canvas stream (Demo + annotated code)

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